How to test the crank sensor?

[Dabigguy]

I am helping a friend with a 1987 GN. He rebuilt the engine and cannot get it started. We have no spark and no injector pulse. We've gone thru the no spark/injector trouble shooting procedure from Vortex Buick and it points to the crank sensor, but he has already replaced it with an Advance Auto model and still no start.

Is there a way to test the sensor with it off and attached to the cars wiring? Thanks guys and gals!!!

 

[salvageV6]

Verify power on the dark green to black wire. Should be 12 volts I think.

Then put a piece of steel in the gap and note the voltage with and without it on the gray/red stripe wire.

Should change from when the metal is in there and out of there reading with the + of the meter on the gray/red and the negative of the meter to the black ground wire.

 

[BOP4ever]

I don't know if it would work like my 96 chevy truck but I had to make a LED test light probe the return line from the sensor .

 

[S10xGN]

Pretty sure the voltage is 5.0, not 12v...

 

[dennisL]

The dark green wire (power) is actually +10V. The crank signal should be 6 - 9V.

 

[salvageV6]

That page in the manual is pretty messed up where thet show the whole system as a unit.
The ecm pinout page is a lot more accurate.
It still can be checked however with a meter.

 

[S10xGN]

The dark green wire (power) is actually +10V. The crank signal should be 6 - 9V.

Hah! You made me dig out my manuals, and you are correct. The voltage on this sensor is 12V.

 

[turbo96max]

be careful, i did some comparison using the vortex no start tree, and i got only 5 volts signal where it wanted 6-9 iirc... then it pointed to short in the cabling, there was nothing wrong w my car it was my chip not giving me injector pulse .. both cam and crank output voltage didnt meet the vortex tree criteria by about 1 volt.

 

[Dabigguy]

Thanks for the replies guys !!! We went thru the factory troubleshooting procedure, checking each wire for proper voltage and/or grounding, and all went well until it came to the crank sensor. There was no triggering, we are trying to figure out if it is the sensor or the wiring. I am working too darn much to be able to help him properly.....I appreciate the input !!!